Centralized traffic controlling system



Oct. 26, 1937. w. w. WENHOLZ CENTRALIZED TRAFFIC CONTROLLING SYSTEMFiled Dec. 8, 1930 3 Sheets-Sheet l QIH INVEN'TQR BY 1 flu? Oct. 26,1937. w. w. WENHOLZ I 2,096,832

CENTRALIZED TRAFFIC CONTROLLING SYSTEM Filed Dec. 8, 1930 s Sheets-Sheet2 WM m MATTORNEY Oct. 26, 1937.

w. w. WEJ NHOLZ CENTRALIZED TRAFFIC CONTROLLING SYSTEM-- Filed Dec. 8,1930 3 Sheets-Sheet 3 I'll-ll II.

sill-ll Illlll lNVENT w. Fad BY [(6 ATTORNEY hw Ill NJ 0 Patented Oct.26, 1937 UNITED STATES PATENT OFFHCE CENTRALIZED TRAFFIC CONTROLLINGSYSTEM Walter W. Wenholz, Rochester, N. Y., assignor to General RailwaySignal Company, Rochester, N.

Application December 8, 1930, Serial No. 500,802

46 Claims.- (01. 246-3) 0 one time, and where following trains areprotected by signal indications of clear, caution and stop the same asin double track signalling where trains can move in one direction only.In. other words, an absolute-permissiveblock or A. P. B. system blocksall opposing trains and pcrmits the movement of following trains withthe usual train spacing. In absolute-permissiveblock signalling systemsof the superimposed manual control type, the starting signals as Well asthe entering signals located at each end of each single track sectionhave superimposed thereon manual control, so that these signals may beheldat stop through. suitable control mechanism controlled from acentral office. A system of this type has been shown in the priorapplication of S. N. Wight, Ser. No. 48,553 filed August 6, 1925.Absolute-permissive-block signalling systems usually include twotumbledown circuits, one for each direction of trafiic through themedium of which the home-anddistant relay for each signal of a singletrack section is controlled by the home-and-distant relay of the signalnext in advance, these tumbledown circuits using a common return wire,so that at least three line wires are necessary, the common wire ofwhich can of course not include any track relay contacts. nal engineersare unwilling to rely on a circuit for railway signalling purposesextending any appreciable distance along the railway track withoutbreaking such circuit for each wire at each track relay, so that as amatter of fact the signal system of the prior application of Wight abovereferred to would require four line wires to carry out this checkingtheory.

In view of the above and other important considerations, it is proposedin accordance with the present invention to employ only two line wiresextending from each signal location to the next signal location in asingle track section, to break both of these line wires at each trackrelay, and to use the same two line wires in each of the two tumble-downcircuits, each section of these tumble-down circuits having a source ofcurrent atone end and a relay at the other end for one direction oftraflic movement, and having a relay at said one end and a source ofcurrent at said other end for movement oif trafiic in the oppositedirection, suitable manu ally superimposed control being employed toCertain .sig-

change the direction of traffic and the direction inwhich thesetumble-down circuits have over lapped control.

Other objects, purposes and characteristic fea tures will be obviousfrom the accompanying drawings and will in part be pointed out in thespecification hereinafter.

In describing the invention in detail, reference will be made to theaccompanying drawings Figs. 1A and 1B which if laid end to endillustrate only one single track section and the adjacent ends of twopassing sidings of a railway signalling system embodying the presentinvention, and to Fig. 2 which shows somewhat more in detail'the wiringfor signals 4 and 6, wired as shown for signal 4 in Fig; 1A and with thehome-distant relays shown conventionally as relays of the polarneutral-retained type.

- Although only one single track section 0 and a portion of two passingsidings PS and 0 PS have been illustrated in the drawings, it is to beunderstood that a large number of single track sections are connected bypassing sidings in practicing the invention, and that the left hand orwest end of the passing siding PS is 1 controlled by apparatus such asshown at the west end of passing siding PS and that similarly theeast'end of passing siding PS is equipped with apparatus such as shownat the east end of the passing siding PS passing siding PS is providedwith a track switch S which track switch may be either manually operatedor may be operated by a switch machine all in a manner as described. inthe prior applicationabove referred to and for convenience no specificmeans for operating the switch S has been illustrated, as is also trueof the track switch S located at the west end of the passing siding PSThe track switch S has associated therewith a main entering signal l, atake-siding entering signal i a main starting signal 2 and a dwarfstarting signal 2 the entering signals of which govern the movement oftrains into the main track and side track, respectively, whereas thestarting signals govern the movement of trains oii of the main track andthe side track, respectively, into the single track section 0.

The east end of the Similarly, the track switch S has associatedtherewith starting signals l and i and entering and are preferably threeindication signals and are controlled by homeand-distant relays throughsuitable means illustrated by dotted lines, so that each signal displaysa clear or green signal when. the ho-me-and-distant relay assumes itsright hand energized position, indicates caution when thelhome-and-distant relay'assumesj its left hand energized position andindicates stop if the home-and-distant relay is deenergized.

7 These various home-anddistant relays have been designated HD with aprefix corresponding to the signal which it controls. In this connectionit may be pointed out that entering and starting signals are notdirectly controlled by their associated home-and-distant relays but arecontrolled through repeater relays designated G with a prefixcorresponding to the number of the signal, these signal relays IG, 2G,1G, and 86 having superimposed detector track circuits and manualcontrol, the manual control of these starting and entering signals beingcarried out through the medium of the east relay ER the east relay ERthe west relay WR and the west relay WR}, controlled from a centraldispatchers oiiice D0, in which the passing sidings are re-' produced inminiature by passing siding PS and PS ,'as indicated. The single tracksection 0 as well as the main track of the passing siding is divided byinsulating joints l0 into track circuit sections, of which the singletracksection 0 con tains track circuits including track'batteries ll,I2, [3, I4, I5, I6, [1, and it for controlling track relays 2T, 3T, 4T,5T, 5T ST, ST, and IT,

whereas the track switch S has associated there with a detector trackcircuit including a track relay 2DT and a battery 26, and thetrackswitch S has'associated therewith a detector track circuitcontaining a track'relay 'lDT'rand 'a track battery it. v V j The maintrack of the passing siding PS is provided with a track relay IT and "abattery 2|, whereas the main track of the passing siding PS is providedwith a track circuitcontaining a track relay 8T and a track battery 'H'.tion is directed to'the. fact that the signals 3 and 4 are oppositesignals and govern trafllc-in opposite directions and a-re'located atthe same point whereas the signals'5 and Bare staggered signals in; thatthey are not located at the same point and also govern trafiic inopposite directions. These staggered signals5 and 6 have.

*fic is set up at intermediate signals is an in- V been illustrated forthe purpose of showing how' the novel circuit arrangement may be appliedto a staggered signaltype A. P. B. system Without the use of more thantwo wires along the .trackeven at a staggered signal location. v

Attention is directed to the fact that signals 4 and 6 are illuminated,signifying that they are indicating either caution or clear, whereas thesignals 3 and 5 are not illuminated conventionally indicating that theyare in-the stop a condition. .This fact that onedirectionof trafherentcondition in the system, and is due to the characteristic that thetumble-down circuit which was last established remains in itsestablished condition even thoughthe starting and entering signals atboth ends of the single track section are thereafter put tostop, as willbe readily understood after the operation of the system has beenconsidered.

Although the control relays ER ER WR and WR may be controlled asillustrated in the drawings or as illustrated in the prior applicawire21.

Atten:

tion of S. Wight, Ser. No; 48,553 above re ferred to, these signals arepreferably controlled by a suitable selector type system, such forin- 7stance as illustrated in the prior application of Preston and Hitchcock,Ser. No. 455,304, filed May 24, 1930. These relays ER EH WR and WE arepreferably two position relays of the.

polar magnetic stick type, as conventionally illustrated by the solidsquare, which relays may be operated to' one position by current of onepolarity and may be operated to the other position by current of thereverse polarity and will remain in the last operated position eventhough their energizing circuits are broken. .The relay" vE1 5 iscontrolled by the lever L located at the central oflice DO through themediumof wire.

fix corresponding to that, of the signal. These directional'stick relaysare controlled in. the usual way as more specifically pointed out in theprior application of S. N. Wight, Ser. No. 120,423 dated July 3, 1926,andgenerally'speaking each include a pickup circuit including a frontcontact of its associated home-and-distant relay and a back contact ofthe track relay next in advance of the signal associated therewith, andhaving a stick circuit including a'back' contact of said as-' sociated,ho'me-and-distant relay '(see circuits of stick relays 2S andlS in'thedrawings).

' It is considered expedient to'first trace all of thecircuits which areshown closed in the drawings .andithen consider the operation of thesystern As shown in thedrawings the back-andforth relay BF is shownenergized through a pick-upcircuits-beginning at the terminal of asuitable battery, contact '32 of the relay WR wires 33 and 34, windingof the relay BF to the terminal'of this same battery; and a stickcircuit'beginning at the terminal (+)..of said battery, the back contact35fof the relay 'IHD, wires 36, stick contact 31 of the relay BF wires38 and 34, winding of the relay BF to the terminal of said battery. 'Iheback-and forth relay BF, on the other hand, is only energized throughits pick-up circuit, which may be traced as follows:beginning at theterminal normally closed contact 40 of-the relay EH wires and 42,winding of the relay BF to the other terminal of the same battery. The

relays BF and BF. have been called back-and- 'forth relays, because aback-and-forth movement of the relay ER is necessary to obtain a,

result.

'The home relay 6BR is shown energized through the followingcircuit-beginning at the ,terminal of a suitable battery, resistanceunit R preferably comprising a resistance of ohms, back contact 44 ofthe'relay 36', wire 45, front contact 46 of the detector track relayIDT, wire 41, back Contact 58 of the. direction relay DR wire 49, frontcontact 58 of the track relayJT, wire 5|, front contact 52 of thetrackrelay'fiT, wire 53, back contact 54 of the directional stick relay 58,wire 55, back contact 56 of y the home-and-d istant relay 5HD, wire 51,windand-distant relay has associated therewith a directional stick relaydesignated S with'a 'pre-.

ing of the home relay GHR, wire 58, back contact 59 of the relay EHD,wire 50, back contact 6| of the relay 58, wire 62, front contact 63 ofthe track relay 6T, wire 94, front contact 65 of the relay lT, wire 69,front contact 91 of the track relay EDT, wire 98, back contact 69 of therelay DB wires 12 and 13, back contact 14 of the relay 8G to the otherterminal of said battery.

With the home relay .iI-IR energized the following energizing circuitfor the home-and-distant relay 61-203 is closed:-beginning at theterminal of a suitable battery, wire 99, polar contact 19 of the relayGHR, wire 80, front contact tI of the relay GHR', wire 82, front contact83 of the relay 5T wire 84, front contact 85 of the relay 6T wire 89,back contact 81 of the relay 5HR. wire 88, winding of the relay SHD,wire 89, back contact 90 of the relay EHR, wire 9!, front contact 92 ofthe relay 6T wire 93, front contact 94 of the relay 5T wire 95, frontcontact 95 of the relay SHR, wire 91, polar contact 98 of the relay BHR,wires 18 and 16, winding of the approach lighting relay AL back to theterminal of the same battery.

With the relay SHD now energized the e'nergiz ing circuit for the relayII-ID may betraced as follows:-beginning at the terminal of a suitablebattery, winding of the approach lighting relay AL wires I02 and I93,front contact I04 of the relay fiHD, wire H15, back contact I93 of therelay 63, wire Ifil, front contact I98 of the track relay 5T, wire Hi9,front contact $9 of the track relay 4T, wire ll, back contact H2 of therelay 33, wire H3, back contact I Hi of the relay 31-113, wire H5,winding of the relay AHD, wire Ilfi, back contact ill of the relay SHD,wire H8, back contact H9 of the relay 38, wire 5%, front contact I2I ofthe track relay 4T, wire I22, front contact I23 of the relay'ET, wireHt, back contact I25 of the relay 68, wire I29, front contact I2! of therelay EHD to the other terminal of the same battery.

With the relay AHD energized the following energizing circuit for thehome relay 21-11) is closed:-beginning at the terminal of a suitablebattery, winding of the approach relay AL wires 30, 53 and I32. frontcontact i553 of the relay iTrID, wire 634, back contact I35 of the relay&8, wire 136, front contact I3! of the relay 3T, wire 539, front contactI39 of the relay 2T, wire I49, front contact lei of the direci tionrelay DB wire I42, winding of the relay ZHD. wire M3, front contact I44of the relay DB wire 5'95, front contact MS of the track relay 2T, wireI41, front contact I98 of the relay 3T, wire I49, back contact I50 ofthe relay 05, wire IEI, front contact I52 of the relay ll-1D, to theother terminal of the same battery.

With the home relay 211D energized the direction relay DB is energizedthrough the follow-- ing circuit:beginning at the terminal of a suitablebattery, front contact I59 of the relay ZHD, wires H55, I55, I51, andI58, winding of the relay DB to the other terminal ofthe same battery.In this connection it should be'noted that the relay DB is energizedthrough a front contact of the relay 21-113, and the relay ZHD isenergized through front contact of the relay DB Obviously, the relay DBwas energized through another of its various energizing circuits at thetime the relay ZHD was picked up. These interrelated circuits wlll bemore particularly considered in connection with the operation of thesystem. Attention is directedto the fact that although the relay 22113is energized, signifying that traffic conditions in advance of signal 2are either clear or caution, the signal 2 controlled by the relay 2G isheld at stop because the circuit for the relay 2G is open at the polarcontact E69 of the control relay EH i Referring to the various circuitsjust traced, and particularly the circuits for the relays ZED, 4HD, andBHD, it will be noted that each of these home-and-distant relays arecontrolled by hom'e-and-distant relays having a higher prefix, exceptthat the relay SI-ID is controlled by the relay 8G which latter relay iscontrolled relay 8HD. Also, it will be noted that the circuit for eachofthese home-and-distant relays includes all of the track relay contactsbetween it and the next signal in advance, and that these track relaycontacts are included in both wires of the circuit, this in order togive an additional assurance against crosses and accidental sticking upof some of these contacts. Attention is further directed to the factthat the relay 61-113 is not directly controlled. by the relay 8G asabove inferred, but is controlled by this relay 86 through the medium ofthe home relay til-EL, this because the relay GHD is located at astaggered signal location.

Each of these various home-and-distant relays has been illustrated as apolar-neutral relay hav-, ing both polar and neutral contacts, but theinvention is not limited to this particular construc-' tion, for in caseof alternating current systems a polar relay of the three-positioninduction type would preferably be used. In a direct current system,such as illustrated, these various home" and-distant relays as well asthe home relays BER, and BHR are preferably relays that will not opentheir neutral contacts upon reversal of current applied to its windings,such for instance as shown in the application of Larson, Ser. No.253,880 filed FebruarylB, 1928, now Patent No.

1,852,210 granted April 5, 1932. These relays- HD andHR, with variousprefixes may also comprise a polar relay connectedv in series with aneutral relay which'will not open its contacts upon reversal of currentin the circuit, the neutral relay being'constructed as shown in theapplication of O. S. Field, Ser. No. 428,090 filed February 13, 1930,now Patent 1,852,406, granted April 5, 1932, and. on the other hand theneutral contacts for these various hcmeea-nd-distant relays and homerelays may be shifted to a slow acting repeater relay which repeats thecondition of energization of such home-and-distant or home relay, sothat the circuit for the next homeand-distant relay in the rear will notactually be broken upon pole changing of the corresponding circuit inadvance.

Studying these various home-and-distant relay circuits it will be notedthat in each of these circuits wires are provided with a source ofcurrent at the east end and a relay at the west end, but that-uponenergization of the relays 3l-ID,

5I-ID and SHR and upon deenergization of the relays 4HD, GED, and SEEeach of these circuits will have a relay on the east end thereof and asource of current on the west end thereof, these various features ofinterlocking will be i more clearly apparent upon consideration of theoperation of the system.

Although no specific circuits have been illus trated for controlling thevarious signals by their respective home relays or signal relays, thesevarious signals may be controlled in any well known way, such forinstance. as illustrated in the prior application of S. N. Wight, Ser.No. 48,553

conditionof occupancy, of the various detector.

' track circuits, the position of the track switches,

and the like, it is to be understood that suitable means such asindicated in any of the prior applications above referred to may beemployed.

Operation As heretofore mentioned, and as manifested by the illuminationof signals 4 and 6, the last direction of train movement was from leftto right, that is from'west to east, and for this reason we 'will assumethat there is a train on the main track of the passing siding PS andthat the operator in the central office DO'wishes to allow this train topass through'the single track section 0 and into the main track of thepassing siding PS It will of course be necessary for the operator toclear the signal 2 before the train under consideration can proceedintothe single track section 0'. The operator Will -therefore move hislever L to its right hand position, and

in so doing will apply current of positive polarity 'to the line wire 25thereby'operating the control relay ER to the right, it'being noted thatthe contact 26 of the lever L will not be connected to energy when thelever L assumes "its right hand position; a a

Movement of the control relay 'ER? to the right deenergizes theback-and-forth relay BF this 7 because the stick circuit for this relayBF is broken at the back contact I54 of the may ZHD.

The relay BF is a slow acting relay, and for this reason current maymomentarily :flow'through the contact 40 of the relay ER assuming itsright hand position through the wire I10, front contact I1I of the relayBF wires I12, 'I56, I51, and I58 to the direction'relay DRE. This Imomentary'completion of the circuitjusttraced is, however, of noimportance at this 'time,-because the relay DB is now energized throughthe front contact of the home relay 2HD. Movement of the contact I60 ofthe relay ER to its right hand position, will however close the.following circuit for the signal relay 2G:beginning at the terminal of asuitable split battery, polar contact I14 of the relay ZHD, wire I15,neutral 'contact I16, wire'I11, switch box contact I18 closed only whenthe track switch S is in its main track position, wire I19, frontcontact I80,

of thedetector track relay 2DT, wire I8I, winding of the relay 2G, wireI82, contact I60 of the V relay ER assuming its right hand position tothe middle point C of this split battery. The completionof the circuitjust traced energized the relay 2G and displays a green proceedindication by the signal 2. In this connection it should be noted thatifthe relay ZHD is energized to the reverse position the polar relay2G.will'be energized to its reverse position and will cause the signal 2to display a'yellow caution signal. j

The east bound train under consideration may now pass oif of the maintrack of the passing sid -1'ng PS in response to the clear signal 2 andinto the single track section O. -As'-soonas this train treads upon thedetector track circuit associated with the switch S the track relayZDYI:

will be deenergized, thereby opening its contact I and actuating thesignal 2 to its stop position or condition. Deenergization of the relay2G will of course pole changecthe energizing circuit for the nexthome-and-distant relay in the rear, thereby causing the display of acaution signal at the entering signal at the west end of the passingsiding PS in accordance with the usual practice, it being understoodthat the entering signals I and 8at opposite ends of thepassingsiding-are interlocked so that only one of the entering signalscan indicate proceed at one time, all as clearly disclosed inthe priorapplication Ser. No.

120,423 above referred to.

The dropping of the detector track relay 2DT not only effectsdeenergization of the relay 2G,

but by theclosure of its contact I84 closes the following pick-upcircuit for the relay 2S:beginning at the terminal of a suitablebattery, front contact I85 of the relay ZHD, wire -I86, back contact I84of the relay ZDT, wires I81 and I 88, winding of the relay 2S, to theother terminal of said battery. As the train in question now passes the.insulating joint I0 adjacent the signal I,. it will shunt the trackrelay 2T, thereby effecting deenergization of the relay 2HD and in sodoing will close the following stick cir-. cuit for the relay2S:beginning atthe terminal back contact I85 of the relay 2HD, wire I89,front contact I of the relay 2S, wires I 9| and I 88, winding of therelay 2S, to the otherterminal v Although dropping of the relay2HD'bythe' opening of its contact I54 will break the circuit heretoforetraced for the direction relay DR this direction relay DR, will remainenergized through the medium of the following auxiliary circuitz-e.beginning at the terminal front contact I93 of the. relay 2S,-wire I94,front contact I95 of the relay DR wires I96, I51 and I58, winding of therelay DR, to the other terminal ofrsaid battery. 7

As the train under consideration proceeds in an easterly direction, itwill drop the track relay 3T and thereafter pick up thetrack relay 2T,and upon its passage of the signal 4 which 4 displays .a clear or greensignal it will drop the track relay 4T and in so doing pick up the stickrelay 4S, which stick relay 4S is controlledin the same way as the relay2S. Picking up of the relay 48 will reverse the polarity of currentapplied to the relay 2HD, and as soon as the rear end of the trainpasses off of the track circuit containing the track relay 8T the relay2HD will be energized to its reverse position and will cause the signal2 to display a caution indication. The

signal 6 is still displaying a caution signal, bea cause the signalrelay 86 under the assumed condition remains deenergized,

The operator in the meantime will have operated his lever L to the righthand position and .will thereby apply current of positive polarity tosuitable splitbattery, polar contact I98 of the relay 8HiD assuming itsright hand position, wire I89, front contact 200 of the relay 8HD, wire20I,

winding of the relay BG, wire 202, front contact 203 of thetrack relay1DT, wire 204, switch box contact 205 closed only if the switchgS", isin the main track position. wire 206. contact 201 of the relay ER to themid-point C of the split battery. Energization of the relay 8G will notonly cause the signal 8 to display a clear or green signal, but willalso pole change the current applied to the circuit for the relay BHR,without opening the neutral contacts 8! and 96 of this relay for reasonsheretofore given, so that this relay GHR, will have its polar contactsmove from its left hand to its right position. With the relay ESHRassuming its right hand energized position instead of its left handenergized position the polarity of current applied to the relay BED isreversed, so that this relay BHD assumes its right hand instead of itsleft hand position and causes the signal 5 to assume a clear instead ofa caution position. The train under consideration is 'now assumed to bemoving in an eastwardly direction between the signals 4 and 5. As thistrain passes the signal 6 it will cause the directional stick relay 68to be picked up, thereby reversing the polarity of current applied tothe relay 4HD, and thereby causing the signal 4 to display a cautionsignal as soon as the rear end of the train passes the signal 6. Also,as the rear end of the train passes the signal 6 the stick relay 4S willagain be deenergized, this because the relay 4H1) picks up, and thisdeenergization of the relay 4S and energization of the relay ll-IDcauses current of positive polarity to be applied to the relay ZED,

thereby causing a clear or green indication to be displayed by thesignal 2 instead of a caution indication. I

Movement of the train under consideration in an eastwardly directionbetween the signals 5 and 5 will of course cause the relaytHD to be deenergized because the track relay GT and 5T will be deenergized duringthis movement of said train, and similarly as the train moves betweenthe signal 5 and the signal 8 the home relay BHR, will remaindeenergized, and it will thereby cause the relay iii-ID which repeatsthe relay BHR to be deenergized, and as soon as the train passes thesignal 8 the detector track relay 1D'I is deenergized thereby openingthe circuit for the signal relay 8G at the contact 293, and therebycausing the signal 8 to display a stop signal. It is of courseunderstood that the signal 8 is thereafter controlled in accordance withthe condition of energization of the home relay 8HD and as soon asthe'train in question passes beyond the detector track circuit 1DT therelay 8G is controlled in accordance with the position of this relayBHD. The home-and-distant relay BHD is of course controlled inaccordance with traffic conditionsin advance as indicated in the priorapplication No. 120,423 above referred to.

Let us now assume that there is a west bound train on the main track ofthe passing siding PS and that the operator Wishes to change thedirection of tram-c movement in the single track section 0. Underordinary working conditions the operator will first restore his lever Lto normal and thereby return the relay ER to normal. Let us howeverassume that for some reason or other, such as a broken line wire, theoperator is unable to change the position of the relay ER which nowassumes its right hand position and causes the starting signal 2 todisplay a proceed indication. The operator now moves his lever L to itsleft hand position signifying permissible west bound entrance of a traininto the single track section 0. This movement of the lever L when itreaches its intermediate position, effects momentary negativeenergization of the wire 30 thereby causing the relay EH to be moved toits left hand position if it has not already assumed such position. Whenthe lever L reaches its extreme left hand position current of negativepo larity is applied to the control relay WR thereby operating thisrelay WR to its left hand dotted position. The relay 1HD is of coursestill deenergized because the direction relay DB is still deenergized,and with the relay lHD deenergized the relay IBF is energized throughits stick circuitheretofore traced. Movement of the relay- WR to itsleft hand position therefore completes the following pick-up circuit forthe relay DB beginning at the terminal of a suitable battery, contact 32of the relay WR. t0 the left, wire 218, front contact-2H of the relay BFwires 212, 213, M4, and 2I5, winding of the relay DB to the otherterminal of said battery.

Picking up of the direction relay DB will of course eil'ectdeenergization of the relay BHR, because the relay 1HD is now connectedto the east end of the line wires connecting signal locations 5 and 8.Deenergization of the relay GHR will effect deenergization of the relay6HD, deenergization of the relay GI-ID will effect the deenergization ofthe relay 4HD, and deenergization of the relay 4HD will effect thedeenergization of the relay. El-ID. In other words, a tumble down havebeen deenergized as soon as the relay ZHD' picked up after it had beendeenergized by passage of the east bound train, thisbecause its stickcircuit including its stick contact 2I1, wires 2i$ and 2I9 and backcontact I54 of the relay ZHD was broken when this relay 2HD picked up.Furthermore, the dropping of the relay 2HD, by the tumble down functionjust explained, opens the front contact I54 of the relay 231D andeffects dropping of the direction relay DB it being understood that therelays BF and 28 are now deenergized. With the direction relay DR nowdeenergized, the following energizing circuit for the home relay 3HD iscompleted:'beginning at the terminal, resistance unit R preferably of100 ohms resistance, back contact 22I of the relay I G, wire 222, frontcontact 223 of the track relay 2DT, wire 224, back contact I4I of therelay DB elements I40, I39, I38, I31, I36, I35, I34, I33, and 226,winding of the relay 3HD, elements 221, I52, I5I, I59, I49, I48, I41,I46, I45, I44, 228, .229, 239. and 23I and back to the terminal of saidbattery. The completion of the circuit just traced will cause the relay3HD to assume its left hand energized position, thereby causing thesignal 3 to display a caution indication.

Picking up of the relay 3HD will cause the following circuit for therelay 5HR. to be completed:beginning at the terminal of a suitablebattery, ,winding of the approaching lighting relay AL35,' elements,I35, 233, II -l, IE9, i I2, III, I10, I59, I08, I91, I09, I95, I94, and234, winding of the relay 5HR, elements 235, I21, I26, I25, I24, I23,I22, IZI, I29, H9, and H8, contact H1 in its energized position, to theother terminal of said battery.

The completion of the circuit just traced .will" energize the relay 5HRto its right hand position, thereby completing an energizing circuit forthe relay 5HlI) which may be traced as follows:beginning. at theterminal of a suitable battery,

. and 249, winding of the relay elements 24! 7 81., 82, 83., 84,85, 86,81, and 242, contact 243 of the relayBI-IR assuming its right handposition to the other terminal of said battery. The completion of thecircuit just traced will energize the relay HD to its right handposition, thereby 7 causing'the signal 5 to display a clear proceedposition.

With the relay 5HD energized the following energizing circuit for therelay 'IHD is closed:

beginning at the terminal of a suitable battelfy, Winding of theapproach lighting relay AL elements 16;", 245, 246, 56, 55, 54; 53, 52,5|, t 59, 49, 48, 24 i, winding of the relay IHD, ele- 'ments 248, 69,68, 6 66, 65, 64, 63, 62, Hand fill, contact 59 of, the relay 5HD in itsattracted position, to the other terminal of said battery. t 7 V Withthe relay IHD now energized toits right hand position and the controlrelay WR assuming'its left hand position the following energizingcircuit for the signal relay 1G. is completed: beginning at the terminalof a suitable split.

' battery, contact 250' of the relay 'IHD, wire 25!,

front contact 252 of the. relay II-ID, wire 253, front contact 254 ofthe track relay IDT, wire 55, switch box contact 256: closed only, whenthe t-ch S is in its main track position,'wire 251,

winding of the relay 1G, wire 258,.contact 259 to display a clear orgreen proceed indication,

thereby allowing the west bound train occupying the main track of thepassing siding PS to proceed into the single track section 0. The trainunder consideration will of course encounter a caution signal when itreaches the signal 3-, this becausa'asassumed, the operator was unableto change the position of either ofthe relays ER or WE at the west endof. the single track section 0. The train can of course proceedatcaution until it reaches the signal I at which time the train crew canget in communication with the operator through the. mediumof'atelephone, preferably located. at the end of each passing siding.

I-t its-thus San that irrespective of the condition of the controlrelays, such as, relays ER. and WR at one end of a single track sectionthe operator may through the medium of the control relays at the otherend ofthe single track section change the direction of train movement insuch'sing le track section. This .is accomplished by reason of theback-and-forth stick relaysBF and BF, these relays enabling thedirection relays DR; or DR. to be picked up only in response to abackand-forth movement of the contacts of the relays'lLR and WRrespectively. These backand-forth relays canbe picked up only with theassociated control relay ER or WR in one position and allow thedirectionrelay'DR or DR. to be picked up only through a front contact ofr the back-and-forth relay and with the control relay ER or WR assumingthe opposite position. Similarly, the direction relay DR, if once pickedup, as for instance in the manner just indicated,

, thereafter can'be held up only through either a holding circuit or astick circuit the holding cir-. cuit of which includes a front contactof the associated. home relay, THD which can only be up with thisdirection relay DR up, and the other or stick circuit of which includesa front contact of the associated directional stick relay 'lSyfrom whichit is apparent that with no train in the single track section, thedirectional stick relay TS must assume its deenergized position, so thatthe directionrelay DB may be deenergized from the oppositeendof thesingle track section, by reason of the fact that the home-and-distantrelay II-ID, associated with such direction relay, is in a tumble-downcircuit energized from the opposite end of thesingle track section. Inother words, to change the direction of traflic movement, thehome-and-distant and home relays are caused to tumble down in onedirection and in sojdoingleffect deenergization of the direction relayat the remote end of the single track section, and with this directionrelay once deenergized the home relays for governing the oppositedirection of traflic will tumble up, so to speak.

' It has already been explained how the operator may set up a directionof traffic to allow a train to move into. one end of a single trackSection even though he hasrno control over thecontrol relays located at,the opposite end of the single track section; Let us now see how thetrain crew may itselfset up its ,own direction of traffic in theevent'that the entire selector system or other control for th variouscontrol relays ER and WR is out of order, and that the operator hasabsolutely nocontrol over the system. In this case,

' the train crew when it is*ready to enter a single track sectionfiwillget into communication with theoperator at the central ofiioe to receiveorders,

as over the telephone system, oreven without any order from the operatorin case the telephone system is out of order, a member ofgthe traincrewwill depress the push button PB 'if they are located at the West end ofthe single track section O-or the push button PI? if they are located atthe east end of this single track section, and in so doing will effectenergization of the'associated direction'relay DR or DB and thereby willcause the direction of trafiic to be changed in exactly the same manneras heretofore described in connection with the west bound train movementthrough the single track section 0, except that the direction relay DBis now picked up by the push button BB where in. thecase. heretofore:considered in detail this relay DR. was picked up by the operation ofthe control relay WR; to its left hand position. Should, however, therelay WR 'be assuming the right hand position, under which conditionthe.

relay 1G cannot be picked up and the signal I cannot be cleared thecall-on. signal CO would be cleared through the front contact 268 ofthe. relay 'IHD and the back contact 261 of the push button P3 Referringto Fig. 1A be noted that the relay2HD is energized over the line Wires[36, and 5449 by a source'of current located at the signal 4. Itwillalso be noted that if relay DR were to be deenergized, that by suchdeenergization of relay DB the line wires--l36-l40 and l45-l49 would beconnected to a source of current located at the signal '2 through themedium of back contact MI and 144 of relay .feeding'track relay 2' I or3T, such momentary deenergization could cause deenergization of therelay DB and as soonas .the crowbar is removed of the drawings, it 'win"there would be a source of energy at each end of the line wires [36-540and 145-549, and the voltages of these sources might be cumulative. Suchsimultaneous application of energy on the opposite ends of the linewires MiG-I40 and I45- l l9 is however not detrimental to these sourcesof current, by reason of the inclusion of the resistance R in thecircuit. Furthermore, such simultaneous application of two sources ofcurrent on the same line circuit should be a very rare and unusualoccurrence. What has been said in regard to the purpose of theresistance R shown in Fig. 1A is also true of the resistance R shown inFig. 1B.

The applicant has thus provided an A. P. B. system with supervisorycontrol from a'central office, which has all of the operatingcharacteristics of commercially recognized practicalabsolute-permissive-block systems, in which he has used less line wiresand in which his circuits are protected by more relay contacts, toassure against various false indications due to crosses or stickingrelay contacts, and in which each home-anddistant relay has itsenergizing circuit checked through the back contact of thehome-and-distant relay for governing opposing train movements, forinstance, home relay 3H1) can only be energized through back contacts ofhome relay 4I-ID, and home relay tHD can only be energized through backcontacts of relay SI-ID. Furthermore, the system is so organized thatupon failure of a portion of or the failure of the, entire manualsupervisory control system, a reversal of direction of trafilc may beset up by the train crew from that end of the single track section fromwhich the train under the control of such train crew must enter. Also,the momentary false closure of a particular home-and-distant relaycircuit, as for instance by a short train, such as a gasoline propelledcar, moving, as for instance,

from the track circuit of relay 21'' into the track circuit of relay 3T,thereby momentarily closing the energizing circuit for the home relay inthe rear, cannot set up any false indication permanently, as is apt tobe the casein absolutepermissive-block systems of earlier construction,this by reason of the fact that the various homeand-distant relays areso interlocked that only one direction of traffic can be set up at onetime, and the system is so organized that the train itself cannot set upsuch direction of traffic, the direction of traffic being determinedentirely by the condition of energization of the direction relays DR andDR located at opposite ends of a single track section. It is of courseunderstood that the intermediate signals 3 and 4 or 5 and 6, togetherwith their associated circuits may be omitted, if desired.

It is, of course, understood that the track switches S and S arepreferably controlled from the central oflice DO, as through the mediumof a switch machine, and that the. starting dwarf signals 2 and i andthe entering signals I and 8 will be cleared in accordance with thedirection of traflic to be set up providing of course that the trackswitches with which they are associated assume the take-siding position,all as shown in the prior applications above referred to.

Fig. 2

In Fig. 2 has been illustrated a little more in detail the wiring forsignals 4 and 6 of two intermediate signal locations, where both ofthese signal locations have their signals located. opposite asdistinguished from having the signals staggered. The home-distant relaystHD and BI-ID are wired the same as is the relay 61-11) for Fig. 1A,that is, energy is applied to the line circuits in identically the samemanner as the relay 4H1) of Fig. 1A applies energy to the line circuitfor the next relay in the rear, and the relays ill-ID and fiI-ID areconnected to the line circuit in exactly the same manner as relay AHD ofFig. 1A is connected to the line circuit. .The signals 3, 4, 5, and 6have been illustrated as three-aspect color light signals, none of thesesignal aspects of green G, yellow Y or red R being lighted, however,unless the approach lighting relay AL associated with that signal isdeenergized. The reference characters employed in Fig. 2 are the same asin Fig. 1A, except that distinctive exponents 4 and 6 have been added.The windings b of the.

HD relays receive their energy conductively from i the windings a, andthese windings a are inductively connected to the main windings of theserelays. The operation of the system to control signals 4 and 6 of Fig. 2is exactly the same as the operation of signal 4 of Fig. 1A, andtherefore need not be repeated.

Having described one rather specific embodiment of the present inventionit is desired to be understood, that the particular embodimentillustrated has been illustrated for the purpose of disclosing thenature of the invention, its operating characteristics and itsunderlying principles, and that the particular embodiment selected hasnot been selected for the purpose of showing the scope of the inventionnor the exact construction preferably employed in practicing the same,and that various changes, modifications and additions may be made toadapt the invention to the particular type of railway system to which itis to be applied, all without departing from the spirit or scope oftheinvention or the idea of means underlying the same, except as demandedby the scope of the following claims.

' What I claim as new is:-

1. In an absolute-permissive-blook signaling system for railroads, asingle track section, signals at each endof said section for governingthe entrance and exit of trains into and out of said section, signals atan intermediate point for governing the movement of trains in bothdirections through said section, a circuit leading from one end of saidsection to said intermediate point for at times controlling a signal atsaid one end and at other times controlling a signal at saidintermediate point, another circuit leading from the other end of saidsection to said intermediate point for at times controlling a signal atsaid intermediate point and at other times controlling a signal at saidother end, and means for at times controlling said one circuit by saidanother circuit and for at other times controlling said another circuitby said one circuit.

2. In an absolute-permissive-block signal system, the combination with asingle track section,

signals for governing the movement of trains through said section, meansfor controlling said signals including two circuits arranged end to endand together extending the length of said section, means for at one timecontrolling one of said circuits by the other circuit and at other timescontrolling said other circuit by said one circuit, and two stick relaysfor determining which of said two circuits shall control the other ofsaid two circuits.

3. In an absolutepermissive-block block signal system, the combinationwith a single track section, signals for governing the movement oftrains signals including two circuits arranged end to end and togetherextending the length of said section, means for at one time controllingone of' said circuits by the other circuit and at other timescontrolling said other circuit by saidione circuit, two stick relays fordetermining WhiCh'Of said two circuits shall control the other of saidtwo circuits, and a control relay controlled from a distant point foreach of said stick relays f controlling the same. 7 4. In anabsolute-pernfissiVe-block signal system, the combination with a singletrack section, signals for governing the movement of trains through saidsection, means for controlling said signals including two circuitsarranged end to end and together extending the length of said section,means for: at onetime controlling one of said circuits by theothertcircuit'and at other times controlling said'other circuit by saidone circuit,

'two stick relays for determining which of said 7 'two circuits shallcontrol the other of said two circuitsa control relay controlled from a.distant point for each of said stick relaysfor controlling the same, anda pick-up circuit for each of said stick relays which when such stickrelay is deenergized can be closed onlyupon a change in the position ofits associated control relay;

5. an absolute-permissive-block signal system, the combination withasingle track section, signals for governing the movement ofiQtrainsthrough said section, means for controlling said signalsincluding' twocircuits arranged end to end and together extending the length of saidsection, means for at one time controlling one of said circuits by theother circuit and at other times controlling said other circuit by saidone circuit, two stick relays for determining which of said two circuitsshall control the other of said two circuits, a control relay controlledfrom a distant point for each of said stick relays for controlling thesame, and a pick-up circuit for each of said stick relays which can beclosed only position of its associated control relay; I V i d 5. manabsolute-permissive-blocksignal systom, the combination with a singletrack section,

signals for governing the movement of trains through said section, meansfor controlling said signals including two circuits arranged end to endand together extending the length oi said section, means for at one timecontrolling '-one of said circuits by the other circuit and at othertimes controlling said other circuit-by said one circuit, two stickrelays for determining which of said two circuits shall control theother of said two circuits, an auxiliary relay for each of said stickrelays, a control relay for each of said stick relays, a circuitior eachauxiliary relay closed only when the associated control relay assumesone position, and a pick-up circuit for each stick relay closed onlywhen the associated control relay assumes anotherpo'sition and then onlyif the associated auxiliaryrelay assumes its ener- V gized position.

'7. In an absolute-permissive block signal system, the combination witha single track section, signals for governing the movement of trainsthrough said section, means for controlling said signals including twocircuits arranged end to end and together extending the length of saidsection, means for at one time controlling one. of

' said circuits by the other circuit and at other times controlling saidother circuit by said one circuit, two stick relaysfor determining whichof said two circuits shall control the other of said two circuits, anauxiliary relay for each of said stick relays, a control relay for eachof said stick relays, a pick-up circuit for each auxiliary relayclosed'only when the associated control relay assumes one position, anda pick-up circuit for 'each stick relay closed only when the associatedcontrol relay assumes another position and then only if the associatedauxiliary relay assumes its energized position.

two circuits, an auxiliary relay for each of said 7 stick relays, acontrolirelay for each of said stick relays, a pick-up circuit for eachauxiliary relay closed only when the'associated control relay as sumesone position, a, stick circuit for each auxiliary relay closed if theassociated stick relay assumes its deenergized position, and a pick-upcircuit for each stick relay closed only when the ssociated controlrelay assumes another position and then only if'the associated auxiliaryrelay assumes itsenergized position.

9. In an absolute permissive-block signaling systemior railroads, asingle track'se'ctiomsigs nals at each end of said section for governingthe entrance andexit of trains into and out of said section, signals atan intermediate point for governing the movement of trains in bothdirections through said section, a. circuit leading from one i 7 end of'said'section to said intermediate point for ,at times controlling asignal at said one end and at other times controlling a signal at saidintermediate point,another circuit leading from the otherend of's'aidsection to said intermediate a point for at times controlling a signalat said intermediate point and at other times controlling a signal atsaid other end, two relays located at said intermediate point one attimes included in one of said circuits and the other at times includedin the other of said circuits, interlocking means for preventing morethan one of said-relays being energized at one time, andmeans forcontrolling said other circuit by said one relay and controlling saidone circuit by said other 1 v relay; 7 r V I V 10. In anabsolute-permissive-block signaling system for railroads, a single tracksection, sig-' nals at each end of said section for governing theentrance and exit of trains into and out of said section, signals at anintermediate point for governing the movement of trains in bothdirections through said section, a circuit leading from one end of saidsection to said intermediate point for a 1 I I at times. controlling asignal at said intermediate point, another circuit leading from theother end of said section to said intermediate point for at times,controlling a signal at said intermediate point and at other timescontrolling a signal at said other end, track circuits having qfront contacts included in said circuits, two relays located at said intermediatepoint one at times included in one of said circuits and the other attimes in lays being energized at one time, and means for controllingsaid other circuit by said one relay and controlling said one circuit bysaid other relay.

11. In a single track railway signalling system, the combination with asingle track section, signals for governing traffic in each directionthrough said section, manually controllable means for determining theclearing of signals for establishing a particular direction of trafficthrough said section, and other manually cOntrollable means forreversing the direction of traffic set up by said first mentionedmanually controllable means through said section, said other manuallycontrollable means being effective irrespective of said first mentionedmanually controllable means.

12. In an absolute-permissive-block signal system, the combination witha single track section, signals for governing the movement of trainsthrough said section, means for controlling said signals including twocircuits arranged end to end and together extending the length of saidsection, means for at one time directly contrlling one of said circuitsby the other circuit and at other times directly controlling said othercircuit by said one circuit, and two stick relays for determining whichof said two circuits shall control the other of said two circuits.

13. In a single track railway signalling system,

the combination with a single track section having an intermediatesignal location, a signal at said location for governing traific in onedirection, a signal at said location for governing trafhe in theopposite direction, a relay for each signal to control the same, and acircuit for each relay including a back contact of the other relay andsaid circuit being energizable only when the track in advance of thesignal for that relay is unoccupied by a train, whereby only one of saidsignals can be cleared .at one time.

14. In a single track railway signalling system, the combination with asingle track section having an intermediate signal location, a signal atsaid location for governing trafiie in one direction, a signal at saidlocation for governing traffic in the opposite direction, av relay foreach signal to control the same, circuit wires for each relay, andcontacts on each relay which if down connect the circuit wires of theother relay to such other relay but if up connect such wires to a sourceof current. 7

15. In a single track railway signalling system,

the combination with a single track section con-'- necting two doubletrack sections, intermediate signal locations each including two signalsone governing traffic in one direction and the other governing traflicin the other direction, a circuit extending from each signal location toan adjacent signal location, and means for controlling each circuitdirectly by the adjacent circuit to constitute a tumble-down arrangementwhich at times operates from right to left and at other times operatesfrom left to right.

16. In a single track railway signalling system, the combination with asingle track section connecting two double track sections, intermediatesignal locations each including two signals one governing traffic in onedirection and the other governing trailic in the other direction, acircuit extending from each signal location to an adjacent signallocation, a relay for each end of each of said circuits, means for attimes energizing each circuit from the right-hand end to energize therelay at the left-hand end and for at other n times energizing eachcircuit from the left-hand end to energize the relay at the right-handend, and contacts on said relays for controlling each of said circuitsby an adjacent circuit.

17. In a single track railway signalling system, the combination with asingle track section con-' necting two double track sections,intermediate signal locations each including two signals one governingtraffic in one direction and the other governing traffic in the otherdirection, a circuit extending from each signal location to an adjacentsignal location, a relay for each endof each of said circuits, means forat times energizing each circuit from the right-hand end to energize therelay at the left-hand end and for at other times energizing eachcircuit from the left-hand end to energize the relay at'the right-handend, a directional stick relay associated with each end of each of. saidcircuits, and contacts on said directional stick relays for at timesapplying current to said circuits.

18. In a single track railway signalling system, the combination with asingle track section connecting two double track sections, intermediatesignal locations each including two signals one governing traffic in onedirection and the other governing traflic in the other direction, acircuit extending from each signal location to an adjacent signallocation, a directional stick relay for each signal, and contacts onsaid directional stick relays for at times energizing said circuits fromone end and 'at other times energizing said circuits from the other end.

19. In a single track railway signalling system, the combination with asingle track section connecting two double track sections,intermeditrollable from a central oflice for permitting clearing ofsignals for only one direction of travel at one time, andother manuallyoperable control means at each end of said single track section forchanging the direction of traific set up by said first mentionedmanually operable means.

20. In a single track railway signalling system, the combination with asingle track section connecting two double track sections, intermediatesignal locations each including two signals one governing traific in onedirection and the other governing traffic in the other direction, acircuit extending from each signal location to an adjacent signallocation for governing said signals, manually operable control meanscontrollable from a central ofiice for permitting clearing of signalsfor only one direction of travel at one time, other manually operablecontrol means at each end of said single track section for changing thedirection of traific set up by said first mentioned manually operablemeans, and visual indicating means for indicating when the direction oftrafiic has bee changed.

21. In a single track railway signalling system, the combination with asingle track section connecting two double track sections, intermediatesignal locations each including two signals one governing trafiic in onedirection and the other governing traffic in the other direction, acircuit extending from each signal location to an adjacent signallocation for governing said signals, manually operable control meanscon:

trollable from a central ofiice for permitting clearing of signals foronly one direction of: travel at one time, other manually operablecontrol means at each end of said single tracksectionfor changingthe'direction of traific set up by said first mentioned manuallyoperable means, and visual indicating means effective only so long -assaid other manually operable'control means is in its operated'conditionfor indicating when the direction of traffic has been changed.

7 22(Route control means for allowing railway trafiic to move in onedirection at one time only over a particular section comprising; acircuit connecting the ends of said section, a first relay at each endof said circuit for manifesting energization of said circuit, a secondrelay at each end of said section for energizing said circuit from thatend, and means for interlocking said first and said second relay at eachend of 'said circuit so that said'circuit cannot be conditioned t o beenergized from that'end if it has already been energized from the otherend.

23 Route control means for allowing railway traffic to move in onedirection at one time only over a particularsection comprising, acircuit connecting the ends of said section, a first relay at each endof said circuit for manifesting energization of said circuit, a secondrelay at each end of said section for energizing saidlcircuit from thatend, and means for interlocking said first and said second relay at eachend of said circuit so that when said circuit is energized from one endsuch energization cannot be interfered" With'by the second relay at theother end. 24. In combination, a stretch of single track over whichtraflic moves in both directions, signals governing the entrance oftrafiic into said stretch, intermediate signals located at intervalsalong the stretch for governing traific in' both directions through" thestretch, all of said signals being capable of indicating stop, caution,and proceed,Imanual1y operable means for separately controlling thesignals'governing the entrance of traffic-into said stretch, ineither-direction, and-l means for rendering said manually operablemeans'inefiective' to cause such entering signals to indicatecaution orproceed unless all of the opposing intermediate signals indicate s p. a

25. In combination, a stretch of, single track' over which trafiic movesin both directions, a first H signal for governing trafiic in onedirection when said first line relay is energized by current of onepolarity and a proceed indication when said first line relay isenergized by current of the other polarity, a second signal forgoverning trafiic in the opposite direction through said stretch, asecond polarized line relay; means con trolled by said second line'relayfor controlling s'aidsecond signal in such manner that said secondsignal indicates stop, caution, or proceed according as said second linerelay is deenergized or is energized by current of one polarity or theother; manually operable means for at times supplyingisaid second linerelay with current of one polarity or the other when the portion of saidstretch between said signals is unoccupied,

and means'for at times supplying said first line.

relay'with current of one polarity orithe, other when the'portion ofsaid stretch between said aocasaa signals is unoccupied and said secondline relay is deonergized. r a,

'26. In combination, a stretch of single track over which traffic movesin both directions, a first signal for governing traffic in onedirection through said stretch, a first polarized line relay, meansefiective when said first line relay is deenergized for causing saidfirst signal to indicate stop, manually operable means for causing saidfirst signal to display a caution indication, when 7 said first linerelay is energized current of one polarity and a proceed indication'whensaid first line" relay is energized by current of the other 1 polarity,a second signal located'at some distance from said first signal forgoverning trafiic in the opposite direction through said stretch,-

a second polarized line relay; means controlled 7 by said second linerelay for controlling said second signal in such manner that said secondsignal indicates stop, caution, or proceed according as said second linerelay is deenergized or is energized by current of one polarity or theother; manually controlled means for at times supplying'said' secondline relay with current of one polarity or the other when the portion ofsaid stretch between said'signals is unoccupied, means for supplyingsaid first line relay with current of one polarity when the portion oftrack between said signals is unoccupied and said second line relay isdeenergized; and means for supplying said first line relay with currentof the other polarity when the portion of track between said signals isunoccupied, said second line relay is dee-nergized, and the portion oftrack immediately beyond said the opposite direction from that governedby. said second signal is occupied.

27. In combination, a stretch of single track 'over which traffic movesin both directions, a first signalior governing trafiic in one directionthrough saidstretch, a first polarized line relay meansefiective whensaid first line relay is deenergized for causingsaidfirst signal toindicate stop, manually operable means for, causing said first signal todisplaya, caution indication when said first line relay is energized bycurrent of one polarity and a proceed indication said first line relayis energized by our ent of the other polarity, a second signal locatedat some distance, from said first signal for governing traffic in theopposite; direction through. said stretch, a second polarized linerelay; meanscon' trolled by said second line relay for controlling saidsecond signal in such manner that said second signalindicates stop,caution, or proceed according as said second line relay is deenergizedor is energized by current of one polarity or the other; manuallyoperable means for at times supplying said second line relay withcurrent of one polarity or'the other when the portion of said nd signalfor trafiic moving in stretch between said signals is unoccupied, and,

said first linerelay is deenergized, and means for" attimes supplying,said first line, relay with current of one polarity or the other whenthe portion of-said stretch between said signals is un- 7 occupied andsaid second line relay is deener- V gized.

28. In combination, a stretch of single track signal indicates stop whenthe relay is deenergized, and means for controlling said relays in suchmanner that a relay associated with a signal which controls traffic inone direction cannot become energized unless the relay associated withthe opposing signal which governs the entrance of traific into the sameportion of the stretch is deenergized.

29. In combination, a stretch of single track over which traflic movesin both directions, signals for governing traffic in one directionthrough said stretch and other signals for governing traffic in theother direction through said stretch, a plurality of line relays oneassociated with each signal and each arranged to control the associatedsignal in such manner that the associated signal indicates stop when therelay is deenergized, and means for energizing each line relay when andonly when the portion of track between the associated signal and thesignal next in advance governing traffic in the same direction isunoccupied and the line relay associated with the signal next in advancegoverning traflic in the opposite direction is deenergized.

30. In combination, a stretch of single track over which trafiic movesin both directions, head block signals governing the entrance of trafficinto said stretch, intermediate signals located at intervals along thestretch for governing traffic in both directions through the stretch, aplurality of line relays one associated with each of said signals andeach arranged to control the associated signal in such manner that theassociated signal indicates stop when the line relay is deenergized, andmeans for controlling said line relays in such manner that the linerelay associated with each head block signal cannot become energizedunless all of the line relays associated with the intermediate signalswhich control traffic in the opposite direction are deenergized and allof the line relays associated with the intermediate signals whichcontrol traflic in the same direction are energized.

31. In combination, a stretch of single track over which trafiic movesin both directions, signals for governing trafiic in one directionthrough said stretch and-other signals for governing traffic in theother direction through the stretch; a plurality of line relays oneassociated with each signal and each arranged to control the signal withwhich it is associated in such manner that the signal will indicatestop, caution, or proceed according as the associated relayisdeenergized or is energized by current of one polarity or the other;means for at times supplying each line relay with current of onepolarity when the portion of track between the signal controlled therebyand the signal next in advance governing traffic in the same directionis unoccupied, the line relay associated with the signal next in advancegoverning trafiic in the same direction is energized, and the line relayassociated with the signal next in advance governing trafiic in theopposite direction is deenergized; and means for at other timessupplying each line relay with current of the opposite polarity when theportion of track between the signal controlled thereby and the signalnext in advance governing traffic in the same direction is unoccupied,the line relay associated with the signal next in advance governingtrafiic in the same direction is deenergized; and the line relayassociated with the signal next in advance governing traflic in theopposite direction is deenergized.

32. In combination, a stretch of single track over which trafiic movesin both directions; a first signal for governing traflic in onedirection through said stretch; a first polarized relay for controllingsaid first signal to the clear, caution and stop condition when saidfirst relay is respectively energized by current of normal polarity, bycurrent of reverse polarity and is deenergized; a second signal forgoverning traffic in the opposite direction through said stretch, asecond polarized relay for controlling said second signal to the clear,caution and stop condition when said second relay is respectivelyenergized by current of normal polarity, by current of reverse polarityand is deenergized, control circuits for each of said polarized relaysso organized that each saidrelay may be energized by current of eithernormal or reverse polarity if said stretch is unoccupied and the otherof said relays is deenergized, and manually operable means for holdingeither of said relays deenergized.

33. In combination, a stretch of railway track divided into sections,signals governing traflic in both directions through said stretch, apolarized line relay and a slow-releasing stick relay for each signal,means operating when a given line relay is closed and the associatedstick relay is open to supply current of normal polarity to the linerelay for the signal next in the rear, means operating when theassociated stick relay is closed to supply current of reverse polarityto the line. relay for the signal next in the rear independently of thegiven line relay, track circuits for said sections for controlling saidline relays, means for energizing each stick relay when a train movingin the direction in which the associated signal governs traffic passessuch signal and for keeping it energized as long as the line relay forsuch signal remains deenergized, and means controlled by each polarizedline relay for energizing the associated signal to display a clear orcaution indication when'its line relay is energized by current of normalor reverse polarity, respectively and to display a stop indication whenits line relay is deenergized.

34. In combination, a stretch of railway track divided into a forwardblock and a rear block and the forward block further divided into aforward section and a rear section, a forward signal and a rear signalfor governing traffic movements through the forward and rear blocks,respectively, a track circuit for each of the sections of said forwardblock each including a track relay, a line relay for controlling saidforward signal energized by a circuit including in series contactsclosed by said track relays in their energized condition,

a polarized line relay for controlling said rear signal, aslow-releasing stick relay, a circuit controlled by a front contact ofsaid first line relay and by a back contact of said stick relay forenergizing said polarized line relay by currentof normal polarity, asecond circuit controlled by a front contact of said stick relay forenergizing said polarized relay by current of reverse polarityindependently of said first line relay, a pick-up circuit for energizingsaid stick relay when a train moves from said rear block into saidforward block, and a stick circuit for said stick relay controlled by aback contact of said first line relay.

35. In combination, a stretch of railway track, signals located atintervals to govern traffic in one direction through the stretch, othersignals located at intervals to govern traflic in the opposite directionthrough the stretch, a sectionalized line wire adapted for use as thecommon line wire in the control of said signals, a traffic lockingcircuit for the stretch having as one conductor the diiierent sectionsof said sectionalized line wire, directional means at each end of thestretch to govern trafiic entering the stretch at. its end and eacharranged to beat times controlled': by the 'trailic locking circuit, acurrent source at each end' of the stretch each adapted to at tlmessupply current to the trafiic'locking circuit for controlling thedirectional means at the opposite end of the stretch, and repeatingmeans including two directional relays at each sectionaliz'ed locationof said line wire said relays being arranged to bridge the trafficlocking circuit from one section of the line wire to the next section'ineither direction and thereby carry through from end to end of thestretch the control effected by'the current'source at one end to thedirectional means at the other end in either direction.

36. In combination, a stretch of railway track, signals located atintervals to govern traflic in one direction through the stretch, othersignals located at intervals togovern traffic in the opposite directionthroughthe stretch,a' sectionalized line wire adapted for use as thecommon line wire in the control of said signals, a trafiic lockingcircuit for the stretch having as one conductor 7 the different sectionsof said sectionalized line wire, directional means at each end of thestretch to govern trafiic entering the stretch at its'end and eacharranged to be at times controlled by the traflic locking circuit, acurrent source at each end of the stretch each adapted to at timessupply current to the traflic locking circuit for controlling the'directionalmeans at the opposite end of the stretch, and repeatingmeans including two directional relays at each 'sectionalized 1o'ca tionof said line wire and arranged to repeat the effect of the trafficlocking circuit from one section of said line wire to the next in eitherdirection and thereby carry through from end to end of the stretch thecontrol eifected by the current a source at one end to the directionalmeans at the other'end'in either direction. 7

'37. In combination, a stretch ofrailway track,

signals located atintervals to govern traflic in one directionthroughthe stretch, other'signals located at intervals to govern traficin the opposite direction through the stretch, a sectionalizedline wireadapted for uselas the common line wire control of said signals,a'ltrafiic locking circuit for the stretch having as one conductor thedifferent sections of said sectionalizedcommon line wire, a currentsource and a relay at each end of the stretch, a manually controlledselector at each end adapted to include either the relay or the currentsource at its end in the traffic looking circuit, repeating means ateach sectionalized location of the common line wire including twodirectional relays controlled by the trafilc locking circuit'andarranged to repeat the effect of the traiilc locking circuit from onesection of the common line Wire to the next in a direction correspondingto the direction from which said'relays are controlled to carry throughtheinfluence effected by the applying of current to the traific lockingcircuit at one end to the relay at the other end, a signal at each endof the stretchtc govern the movement of trafiic 'into the stretch,

and means controlled by the relay at the same endof the stretchfor'clearing said signal.

38. In combinatioma'stretch of railway track, 7

signals located at intervals to govern traffic in one direction throughthe stretch, other signals located at'intervalsto govern trafiic in theoppo site directionthrough the stretch, asectionalized 'line wire forthe stretch adapted for use as the common 'line wire in the control ofsaid signals, a trafiic locking circuit for the stretch arranged intoaplurality of sections each section'of which includes a correspondingsection of said common line wire, a relay'and a'current source at eachend of the stretch, a manually controlled selector at each end adaptedto include either the relay or the current source at its endinthe'trafiic locking circuit, 'repeating'means at eachjunction 'ofadjacent sections of the traflic locking circuit including twodirectional relays controlled by the traffic locking circuit andarranged to repeat the effect of the trafilc locking circuit from onesection to the next'in the direction corresponding to that from whichsaid relays are controlled to carry through'the influence effected byapplying current to the trafiic locking circuit at either end of thestretch to the relay at the other end; a signal at each end of thestretch to govern the movement of traflic intothe stretch, and.

means controlled by the relay at the same end of the stretch forclearing said signal.

39. In combination, a stretch of railway track, signals located atintervals to govern trafiic in one direction through the stretch, othersignals located at intervals to govern trafiic in the opposite directionthrough the stretch, a sectionalized line wirefor thestretch adapted foruse as the" 7 common line wire in the control of said signals, a trafficlocking circuit for the stretch arranged into a plurality of sectionseach section of which includes a corresponding section of said commonline wire, a relay and a current source at each' end of the stretch, amanually controlled selector at each end adapted to includeeither therelay or the current source at its end in the trafiic looking circuit,repeating meansat each junction of adjacent sections of the trafficlocking circuit including two directional relays controlledby thetraiiic locking circuit and arranged to supply current to eitheradjacent section in response to being controlled from the other adjacentsection, to thereby carry through the influence effected by applyingcurrent to the trafiic locking circuit at either end of the stretch tothe relay at the other end, a signal at e'achend; of the stretch togovern the movement of trafiic into the stretch,

and meansv controlled by the relay at the same end of the'stret'ch forclearing said signal.

40. In combination, a stretch of railway track, signals located atintervals to govern trafiic in one direction through the stretch,"0thersignals located at intervals to govern trafiic in the opposite directionthrough the stretch, a sectionalizcdl line wire for the stretch adaptedfor use as the common line wire in the control of said signals,

a traffic locking circuit for the stretch arranged into a plurality ofsections each section of which includes a corresponding section of saidcommon line wire, means at each end of the stretch each tion to therebysupply current to the relay at} either end of the stretch in response tocurrent supplied to the traflic locking circuit at the end opposite thatrelay.

41. In combination, a stretch of railway track arranged into tracksections each of which is provided with the usual track circuitincluding a track relay, a trafiic locking circuit extending along thestretch arranged into a plurality of different sections with eachsection including a front contact of each track relay oi the tracksections adjacent that section of the traffic locking circuit, a sourceof current and a directional relay at each end of the stretch, manuallycontrolled means at each end to include either the current source or therelay at its end in the trafiic looking' circuit, repeating means ateach junction of adjacent sections of said traffic locking circuitincluding a current source and two directional relays controlled by thetraffic locking circuit and arranged to supply current to eitheradjacent section when controlled by current from the other adjacentsection whereby under clear traffic conditions the relay at either endof the stretch will become energized when current is supplied to thetraific locking circuit at the other end, a signal at each end of thestretch to govern the movement of traiiic into the stretch, and meanscontrolled by the relay at the same end of the stretch for clearing saidsignal.

42. In combination, a stretch of railway track arranged into tracksections each of which is provided with the usual track circuitincluding a track relay, a traffic locking circuit extending along thestretch arranged into a plurality of diiierent sections with eachsection including a front contact of each track relay of the tracksections adjacent that section of the trafiic locking circuit, a sourceof current and a directional relay at each end of the stretch, manuallycontrolled means at each end to include either the current source or therelay at its end in the trafiic locking circuit, repeating means at eachjunction of adjacent sections of said traffic locking circuit includingtwo directional relays controlled by the trafiic locking circuit andarranged to supply current to either adjacent section when controlled bycurrent from the other adjacent section, to thereby carry through underclear traific conditions of the stretch the influence effected bysupplying current to the traific locking circuit at one end of thestretch to the relay at the opposite end for energizing that relay, asignal at each end of the stretch to govern the movement of traflic intothe stretch, and means controlled by the relay at the same end of thestretch for clearing said signal.

43. In combination, a stretch of railway track divided into tracksections each of which is provided with the usual track circuitincluding a track relay, signals located along said stretch and arrangedto govern traflic in both directions, a sectionalized line wire for thestretch adapted for use as the common line wire in the control of saidsignals, a traffic locking circuit for the stretch arranged into aplurality of sections each section of which includes a correspondingsection of the sectionalized line wire and a front contact of the trackrelay of each track section adjacent that section of the traffic lockingcircuit, means at each end of the stretch adapted to at times supply acontrol current to the trafiic locking circuit, a directional relay ateach end of the stretch controlled by the trafiic locking circuit, twodirectional relays at each junction of adjacent sections of the trafficlocking circuit controlled by said circuit and arranged to supplycurrent to one adjacent section when controlled by current from theother adjacent section and to supply current to said other adjacentsection when controlled by current from said one adjacent section forenergizing the relay at the end of the stretch opposite that at whichcurrent is supplied to the trafiic locking circuit, a signal at each endof the stretch to govern the movement of traffic through the stretch,and means for clearing said signal when the relay at its end of thestretch becomes energized.

44. In combination, a stretch of railway track divided into sections, atrack circuit incuding a track relay for each track section, a linecircuit for the stretch divided into sections each including frontcontacts of the track relays of the track sections adjacent such linecircuit section, a source of current and a directional relay at each endof each section of the line circuit, manually controlled means at eachend of the stretch for selectively including in the section of the linecircuit having one end adjacent said means the source of current ordirectional relay at that end of said section, means at each junction oiadjoining sections of the line circuit for including in each of saidsections the source of current or directional relay at the adjacent endof such section according as the directional relay at the adjacent endof the other adjoining section is energized or deenergized, a signal ateach end of the stretch to govern the movement of trafiic through thestretch, and means controlled by the directional relay at the same endfor controlling said signal.

45. In combination, a stretch of railway track, a signal at each end ofthe stretch to govern the movement of trafiic through the stretch, aline circuit for the stretch divided into sections, a source of currentand a directional relay at each end of the stretch, manually controlledmeans at each end of the stretch for selectively including in the endsection of the line circuit adjacent said means its source of current ordirectional relay, repeating means at each junction of adjoiningsections of the line circuit efiective to include a source of current ineither of said sections at the end adjacent such junction when the otheradjoining section is energized at the end remote from such junction, andmeans controlled by each directional relay for clearing the signal atthe same end of the stretch.

46. In a signaling system for railroads, the combination with a sectionof railway track over which traific moves in both directions, signalsfor governing trafiic in both directions over said section, a signalingcircuit associated with said section, two relays one at each end of saidcircuit, each of said relays being of the polar-neutral type opening itsneutral contacts when deenergized, means for connecting one or the otherof said relays to said circuit according to the direction in whichtraffic is to move over said section, means controlled by neutral andpolar contacts of said relays for governing said signals, and meanscontrolled by the presence of a train in said section for opening saidcircuit to deenergize the one of said tworelays then connected to saidcircuit and thereby cause the corresponding signal to indicate stop solong as said section is occupied.

WALTER W. WENHOLZ.

